# Relationship history for MSHA mine 4608069

Current hierarchy: **Hardesty John R Jr-Larry A Myers → Preston Energy Inc → Black Bart**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **controller_controls_mine:** Hardesty John R Jr-Larry A Myers Et Al → Black Bart; 1974-03-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Preston Energy Inc → Black Bart; 1991-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hardesty John R Jr-Larry A Myers Et Al → Preston Energy Inc; 1991-07-01 to current/open; source msha-controller-operator-history